The dispersion and physicochemical behaviors of CuO-CoO binary metal oxides supported on gamma-Al2O3 were characterized by XRD, LRS, XPS, H-2-TPR, and in situ FT-IR techniques. Their activities were evaluated by NO-CO model reaction. The results indicated that (a) for lower loadings, CuO and CoO were able to be highly dispersed on the surface of gamma-Al2O3 support; (b) the interaction between dispersed CuO and CoO upon gamma-Al2O3 was discussed in the view of incorporation model. According to this model and obtained results, the surface dispersed Cu-O-Co species were considered to exist on the surface of gamma-Al2O3; (c) CO or/and NO adsorption FT-IR results evidenced that the surface dispersed copper species could be reduced to lower valence by CO and the NO adsorption species converted with the increase in the temperature; (d) the surface dispersed Cu-O-Co species could be reduced to active Cu-square-Co species by CO among the mixture atmosphere. The formation of the surface synergetic oxygen vacancy (SSOV) was a crucial factor in the process of the NO-CO reaction. And a possible reaction pathway was tentatively proposed to discuss the NO-CO reaction based on all of these results. (C) 2012 Elsevier Inc. All rights reserved.